In flat panel displays, organic light-emitting diode (OLED) display panels have many advantages, such as self luminescence, fast response, wide angle of view, high brightness, bright coloring and light weight and so on, and the OLED display panels have attracted extensive attentions.
According to a difference of light-emitting surface, the OLED display panels are divided into top light-emitting type OLED display panels and bottom light-emitting type OLED display panels. At present, the proportion of the OLED display panels in large size products is becoming larger and larger, it is foreseeable that OLED display panels will continue to develop rapidly in the future. In a case that bottom light-emitting technology is applied to large size OLED display products, a problem of low aperture ratio of the OLED display products is occurred, which is unable to meet the requirements of OLED display products for display effect, therefore, top light-emitting technology is required to be developed. In the top light-emitting technology, in order to increase transmittance of light, a cathode of the OLED display panel is required to be made of a thin transparent conductive film, but impedance of the thin transparent conductive film is very large, a large voltage drop is occurred in a case that a current flows through the cathode, which affects the uniformity of the brightness of the OLED display panel.